• Journal of Ecology and Environment
• /
• 제41권9호
• /
• pp.256-264
• /
• 2017

Background: The aim of this study was to clarify the relationship between the sexual reproduction and the resource allocation in a natural Polygonatum humile population grown in a temperate mixed forest gap. For this aim, the plant size, the node which flower was formed, the fruiting rate, and the dry weight of each organ were monitored from June 2014 to August 2015. Results: Firstly, in 3-13-leaf plants, plants with leaves ${\leq}8$ did not have flowers and in plants with over 9 leaves the flowering rate increased with the number of leaves. Among plants with the same number of leaves, the total leaf area and dry weight of flowering plants were larger than those of non-flowering plants. The minimum leaf area and dry weight of flowering plants were $100cm^2$ and 200 mg, respectively. Secondary, the flowers were formed at the 3rd~8th nodes, and the flowering rate was highest at the 5th node. Thirdly, cumulative values of leaf properties from the last leaf (the top leaf on a stem) to the same leaf rank were greater in a plant with a reproductive organ than in a plant without a reproductive organ. Fourthly, fruit set was 6.1% and faithful fruit was 2.6% of total flowers. Biomasses of new rhizomes produced per milligram dry weight of leaf were $0.397{\pm}190mg$ in plants that set fruit and $0.520{\pm}0.263mg$ in plants that did not, and the difference between the 2 plant groups was significant at the 0.1% level. Conclusions: P. humile showed that the 1st flower formed on the 3rd node from the shoot's base. And P. humile showed the minimum plant size needed in fruiting, and fruiting restricted the growth of new rhizomes. However, the fruiting rate was very low. Thus, it was thought that the low fruiting rate caused more energy to invest in the rhizomes, leading to a longer rhizome. A longer rhizome was thought to be more advantageous than a short one to avoid the shading.

• Journal of Radiation Protection and Research
• /
• 제47권3호
• /
• pp.143-151
• /
• 2022

Background: After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, biological alterations in the natural biota, including morphological changes of fir trees in forests surrounding the power plant, have been reported. Focusing on the terminal buds involved in the morphological formation of fir trees, this study developed a method for estimating the absorbed radiation dose rate using radionuclide distribution measurements from tree organs. Materials and Methods: A phantom composed of three-dimensional (3D) tree organs was constructed for the three upper whorls of the fir tree. A terminal bud was evaluated using Monte Carlo simulations for the absorbed dose rate of radionuclides in the tree organs of the whorls. Evaluation of the absorbed dose targeted ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs, the main radionuclides subsequent to the FDNPP accident. The dose contribution from each tree organ was calculated separately using dose coefficients (DC), which express the ratio between the average activity concentration of a radionuclide in each tree organ and the dose rate at the terminal bud. Results and Discussion: The dose estimation indicated that the radionuclides in the terminal bud and bud scale contributed to the absorbed dose rate mainly by beta rays, whereas those in 1-year-old trunk/branches and leaves were contributed by gamma rays. However, the dose contribution from radionuclides in the lower trunk/branches and leaves was negligible. Conclusion: The fir tree model provides organ-specific DC values, which are satisfactory for the practical calculation of the absorbed dose rate of radiation from inside the tree. These calculations are based on the measurement of radionuclide concentrations in tree organs on the 1-year-old leader shoots of fir trees. With the addition of direct gamma ray measurements of the absorbed dose rate from the tree environment, the total absorbed dose rate was estimated in the terminal bud of fir trees in contaminated forests.

• Journal of Plant Biology
• /
• 제28권4호
• /
• pp.329-332
• /
• 1985

A simple new device for obtaining very clear epidermal imprints for light microscopic studies is discussed. This new device is developed from“Britfix”(polystyrene cement) which is non-toxic to the plant organs. It involves direct application of the material on the desired surface of the plant organ to obtain thin, transparent replica. From the present investigation“Britfix”is found to be useful for the study of epidermal anatomy, morphology and physiology. Epidermal imprints can be mounted on the microscope slide without a mounting medium. Permanent slide of these imprints can be kept for any desired period without any deterioration of the replica.

• Toxicological Research
• /
• 제18권1호
• /
• pp.31-41
• /
• 2002

The present study was conducted to investigate the potential subacute toxicity of plant sterol esters by a 4-week repeated oral dose in Sprague-Dawley rats. The test article was administered once daily by gavage to rats at dose levels of 0, 1000, 3000, and 9000 mg/kg/day for 4 weeks. During the test period, clinical sign, mortality, body weights, food and water consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross finding, organ weight, and histopathology were evaluated. A reduction in the body weight was observed in females of the 9000 mg/kg group on day 27 after the initiation of treatment, but not in males of the group. There were no treatment-related effects on mortality, clinical sign, food and water consumption, ophthalmoscopy, urinarlysis, hematology, serum biochemistry, necropsy findings, organ weights, and histopathology in any treatment group. Based on these results, it was concluded that the 4-week repeated oral dose of plant sterol esters resulted in suppressed body weight in female rats at a dose level of 9000 mg/kg/day. In the condition of this study, target organ was not observed and the no-observed-adverse-effect level (NOAEL) was considered to be 9000 mg/kg/day for males and 5000 mg/kg/day for females.

• Journal of Plant Biotechnology
• /
• 제44권3호
• /
• pp.271-286
• /
• 2017

GROWTH-REGULATING FACTOR (GRF) genes encode plant-specific transcription factors containing two conserved QLQ and WRC domains and play critical roles in regulating the growth and development of lateral organs, such as cotyledons, leaves, and flowers. To explore the agricultural potential of Brassica rapa GRF genes (BrGRFs), the researchers isolated seven BrGRFs (BrGRF3-1, 3-2, 5, 7, 8-1, 8-2, and 9) and constructed BrGRF-overexpressing Arabidopsis thaliana plants (BrGRF-OX). BrGRF-OX plants developed larger cotyledons, leaves, and flowers as well as longer roots than the wild type. The increase in size of these organs were due to increases in cell number, but not due to cell size. BrGRF-OX plants also had larger siliques and seeds. Furthermore, BrGRF-OX seeds produced more oil than the wild type. RT-PCR analysis revealed that BrGRFs regulated expression of a wide range of genes that are involved in gibberellin-, auxin-, cell division-related growth processes. Taken together, the data indicates that BrGRFs act as positive regulators of plant growth, thus raising the possibility that they may serve as a useful genetic source for crop improvement with respect to organ size and seed oil production.

• Nuclear Engineering and Technology
• /
• 제55권2호
• /
• pp.725-733
• /
• 2023

The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, H_p(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting H_p(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

• Molecules and Cells
• /
• 제21권1호
• /
• pp.147-152
• /
• 2006

Most plant organs develop from meristems. Rice FON1, which is an ortholog of Clv1, regulates stem cell proliferation and organ initiation. The point mutations, fon1-1 and fon1-2, disrupt meristem balance, resulting in alteration of floral organ numbers and the architecture of primary rachis branches. In this study, we identified two knockout alleles, fon1-3 and fon1-4, generated by T-DNA and Tos17 insertion, respectively. Unlike the previously isolated point mutants, the null mutants have alterations not only of the reproductive organs but also of vegetative tissues, producing fewer tillers and secondary rachis branches. The mutant plants are semi-dwarfs due to delayed leaf emergence, and leaf senescence is delayed. SEM analysis showed that the shoot apical meristems of fon1-3 mutants are enlarged. These results indicate that FON1 controls vegetative as well as reproductive development by regulating meristem size.

• 한국작물학회지
• /
• 제30권2호
• /
• pp.154-157
• /
• 1985

본 시험은 6월 14 일에 4년생 인삼 식물체의 각 기관별, 10월 1 일에 6년생을 근상태별로 구분하여 호흡량을 측정하였던 바 그 결과는 다음과 같다. 1. 기관별 호흡량은 유과≒엽>화경>경≒근의 순이었다. 2. 15$^{\circ}C$~3$0^{\circ}C$ 사이에서의 기관별 호흡계수는 유과 2.39, 엽 1.75, 근 1.57, 경 1.17, 화경 1.16이었다. 3. 채굴 당시 대편삼(117$\pm$8.8g)과 소편삼(54$\pm$4.0g)간에 호흡량의 차이는 인정되지 않았다. 4. 근내 수분함량이 감소할수록 호흡량은 저하되었으며 그 정도는 소편삼에서 현저하였다. 5 . 건전삼에 비해 근적변삼에서 근호흡량이 현저히 많았다.

• 생명과학회지
• /
• 제11권2호
• /
• pp.111-120
• /
• 2001

The pathological aspects of purified ricin from the seeds of the castor oil plant, Ricinus communis, were examined, using light and transmission electron microscopy. ICR mice were exposed to ricin by peritoneal injection with 100 ng/1 $m\ell$ PBS(pH 7.0) mouse and histological observations on the liver, spleen, thymus, lung and heart were carried out at intervals up to 48 h after exposures. All the organs examined were damaged by ricin. Among the organs, the spleen and thymus; immune organs were the most sensitive to ricin, whereas the effect delayed in the liver, lung and heart. Furthermore, the immune cells in each organ were the most sensitive to ricin. Accordingly, the effect of ricin on the organs seems to be affected by the immune cells existed in each organ, In each organ, the immune cells showed apoptotic changes, while the capillary endothelial and parenchymal cells showed necrotic changes.

• 한국자원식물학회지
• /
• 제14권2호
• /
• pp.152-156
• /
• 2001

최근 중국에서 도입되어 경북 북부지방을 중심으로 재배면적이 확대되고 있는 백출의 재배기술확립 시험의 일환으로 화기제거가 생육과 수량에 미치는 영향을 구명하기 위하여 시험 수행 한 결과를 요약하면 다음과 같다. 1. 백출의 화기제거에 따른 지상부 생육은 무제거에 비해 화기제거에서 초장은 1.7∼2.5cm정도 화기가 제거된 만큼 짧았으며 엽의 크기, 경수와 경직경은 차이가 없었으나 지상부 생체중은 48∼60% 감소되었다. 2. 백출의 화기제거시기별 화기생체중은 화기제거시기가 늦어질수록 무거워져 개화직후에는 주당 39g으로 지상부 생 체 중의 60%를 차지 하였다. 3. 화기제거에 따른 지하부 생육은 무제거에 비해 화뢰출현기제거(7월 15일)와 개화전제거(8월 20일)에서 근경장, 근경직경 등이 컷으며 건근경수량도 유의하게 증수되었는데 화뢰출현기제거구는 290.5kg/10a으로 무제거구보다 40% 증수되어 가장 많았다. 4. 정유함량은 무제거구 0.71m1/50g에 비해 화뢰출현기제거는 12% 개화전 제거는 9%증가한 것으로 나타났으나 개화후 제거는 차이가 없었다.